And, to throw another wrench into this speaker the first version 8ohm from 85-86 sounds very different than the 16 ohm versions of today. I picked up a 1988 800 cab with the 8 ohm Vintages...These are warm, fat sounding speakers that have a much more 'relaxed' top end that differs greatly to the later 90s 16 ohm version. They almost sound like G12 65s with a more prominent midrange.
OP, is there a stamp on the frame anywhere? Date codes used to be there...